1. Field of the Invention
The present invention relates to a contact magnetic disk apparatus and, more particularly, to a contact magnetic disk apparatus for recording/reproducing information by bringing the contact pads of a magnetic head into contact with a magnetic disk surface coated with a lubricant.
2. Description of the Prior Art
FIGS. 1A and 1B, and 2 show a conventional example. Referring to FIGS. 1A and 1B, a magnetic head 53 is held on the surface of a magnetic disk 50, rotated in the direction of an arrow D1, through a suspension 51 and an arm 52. A recording/reproducing element 54 and contact pads 55 are fixed to the magnetic head 53. The contact pads 55 are urged against the magnetic disk surface by the suspension 51. Along with the operation of an actuator 56, the magnetic head 53 is moved in substantially the radial direction of the magnetic disk 50. The section of each contact pad 55 which is parallel to a slider surface 53a of the magnetic head 53 is formed into an elliptic shape having a minor axis in the radial direction of the magnetic disk 50. The two contact pads 55 are arranged in the radial direction of the magnetic disk 50. In the magnetic disk 50, a substrate 61 at the center is sandwiched by magnetic films 62, protection films 63, and lubricant films 64 in the order named, as shown in FIG. 2. Hence, the contact pads 55 of the magnetic disk 50 are kept in contact with the lubricant film 64 of the magnetic disk 50. Wear of the magnetic disk surface is prevented while realizing a high recording density.
In general, the substrate 61 is made of glass or an aluminum alloy coated with a nickel-phosphorus plating film. The magnetic films 62 are made of a cobalt alloy, e.g., CoPtCr or CoCtTa. The protection films 63 are made of carbon. The lubricant films 64 contain perfluoropolyether and the like.
In the above conventional example, rotation of the magnetic disk generates a centrifugal force to move and scatter the lubricant, leading to a decrease or nonuniformity in thickness of the lubricant films. In this case, the lubricant may become insufficient and the contact portions may accordingly be worn, leading to a recording/reproducing error or erroneous erasure of the recorded information.
The present invention is made on the basis of the following situation. Namely, the present inventors experimentally found that a constant relationship was present between the operation of a contact magnetic head driven by an actuator and the thickness decreasing tendency of the lubricant.